The main predators of Emerita are fish in the eastern Pacific Ocean, the barred surfperch ( Amphistichus argenteus) is particularly important. ![]() ![]() Longshore drift may also drag Emerita laterally along a beach. As the tide falls, the sand is allowed to settle when Emerita detects this, it uses the temporary liquefaction from a breaking wave to emerge from its burrow, and is carried down the beach by the wave action. This may be detected by the physical characteristics of the sand. (Also see Fluidization.)Īs the tide changes, Emerita changes its position on the beach most individuals stay in the zone of breaking waves. The digging requires the sand to be fluidised by wave action, and Emerita must bury itself in the correct orientation before the wave has passed to be safe from predators. During this action, the carapace is pressed into the sand as anchorage for the digging limbs. Unlike mud shrimp, Emerita burrows tail-first into the sand, using the pereiopods to scrape the sand from underneath its body. Ecology and behaviour Įmerita is adept at burrowing, and is capable of burying itself completely in 1.5 seconds. Other genera with the same name have been rejected for nomenclatural purposes these were published by Laurens Theodorus Gronovius (1764) and Friedrich Christian Meuschen (17). emeritus), because at one time, it was the only species in the genus. ![]() The type species is Cancer emeritus (now E. The genus Emerita was erected by Giovanni Antonio Scopoli in his 1777 work Introductio ad Historiam Naturalem. analoga, a species living along the Pacific coast of North America, is more closely related to African species than it is to other New World species. The use of molecular phylogenetics has shown, however, that E. The Old World species had been widely thought to form a monophyletic group, as did the New World species. Emerita talpoida (Say, 1817) – eastern North America.Emerita rathbunae Schmitt, 1935 – western Central America.Emerita portoricensis Schmitt, 1935 – Caribbean Sea.Emerita karachiensis Niazi & Haque, 1974 – Pakistan.Emerita holthuisi Sankolli, 1965 – western India, Persian Gulf, and Red Sea.Emerita emeritus (Linnaeus, 1767) – South Asia and Southeast Asia.Emerita brasiliensis Schmitt, 1935 – southeastern Brazil and northeastern Brazil.Emerita benedicti Schmitt, 1935 – Gulf of Mexico.Emerita austroafricana Schmitt, 1937 – southeastern Africa and Madagascar.Emerita analoga (Stimpson, 1857) – western North America and western South America.The genus is common on both coasts of the United States and along the Atlantic coast of Africa the related genus Hippa is found across the Indo-Pacific, including Australia. Most individual species, however, are restricted to smaller areas, and their ranges rarely overlap. The genus as a whole has a broad distribution in tropical and subtropical regions. austroafricana, down to 2.5 mm (0.098 in) carapace length in E. Females are around 8–37 mm (0.31–1.46 in) in carapace length, depending on the species, while males vary from a similar size to females in E. ![]() Males are typically smaller than females, and in some species, such as Emerita rathbunae, the minute males live attached to the legs of the female. It has feathery antennae, which are used to filter plankton and detritus from the swash. It has a tough exoskeleton and can hold its appendages close to the body, allowing it to roll in the tidal currents and waves. Description Įmerita has a barrel-shaped body. These small animals burrow in the sand in the swash zone and use their antennae for filter feeding. Emerita is a small genus of decapod crustaceans, known as sand crabs, or mole crabs.
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